# Creating an array containing sums of combinations of ranges
**URL:** https://rubytalk.org/t/creating-an-array-containing-sums-of-combinations-of-ranges/65269
**Category:** ruby-talk
**Created:** [14 April 2012 23:54 UTC](https://rubytalk.org/t/creating-an-array-containing-sums-of-combinations-of-ranges/65269 "2012-04-14T23:54:41Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@7stud2](https://rubytalk.org/u/7stud2)
#### Post date: [14 April 2012 23:54 UTC](https://rubytalk.org/t/creating-an-array-containing-sums-of-combinations-of-ranges/65269/1 "2012-04-14T23:54:41Z")
I've got a puzzle I haven't been able to solve. I have two user-provided
arrays that look something like this:
[1..2, 2..3]
and
[2, 3]
I need to produce an array containing every possible sum of the ranges
multiplied by the corresponding member of the second array. i.e. if the
first array is [n, m] and the second array is [x, y], I need an array
containing every possible (nx + my).
Normally I'd do a couple of nested loops, but I need the arrays can be
of arbitrary lengths.
How should I go about this?
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### Author:  [@Ralph\_Shnelvar](https://rubytalk.org/u/Ralph_Shnelvar)
#### Post date: [15 April 2012 01:54 UTC](https://rubytalk.org/t/creating-an-array-containing-sums-of-combinations-of-ranges/65269/2 "2012-04-15T01:54:57Z")
Jeff,
Saturday, April 14, 2012, 5:54:41 PM, you wrote:
> I've got a puzzle I haven't been able to solve. I have two user-provided
> arrays that look something like this:
> [1..2, 2..3]
> and
> [2, 3]
> I need to produce an array containing every possible sum of the ranges
> multiplied by the corresponding member of the second array. i.e. if the
> first array is [n, m] and the second array is [x, y], I need an array
> containing every possible (nx + my).
> Normally I'd do a couple of nested loops, but I need the arrays can be
> of arbitrary lengths.
> How should I go about this?
Could you give some more examples. Your English is a bit ambiguous.
Have you thought about using something like Cucumber to specify the problem?
Ralph Shnelvar
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### Author:  [@7stud2](https://rubytalk.org/u/7stud2)
#### Post date: [15 April 2012 02:49 UTC](https://rubytalk.org/t/creating-an-array-containing-sums-of-combinations-of-ranges/65269/3 "2012-04-15T02:49:16Z")
hi Jeff,
have you checked out Array#product ? seems like that might do the
trick for you...
a1 = ['n', 'm']
a2 = ['x', 'y']
p a1.product(a2)
=\> [["n", "x"], ["n", "y"], ["m", "x"], ["m", "y"]]
if your first array is composed of ranges, those can easily be
converted into arrays...
hth-
- j
> **···**
>
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> Posted via [http://www.ruby-forum.com/](http://www.ruby-forum.com/).
---
### Author:  [@7stud2](https://rubytalk.org/u/7stud2)
#### Post date: [15 April 2012 03:47 UTC](https://rubytalk.org/t/creating-an-array-containing-sums-of-combinations-of-ranges/65269/4 "2012-04-15T03:47:55Z")
Jake,
That's exactly what I was looking for. Thank you!
> **···**
>
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> Posted via [http://www.ruby-forum.com/](http://www.ruby-forum.com/).